Electric heating



Jan. 13, 1953 s. J. TEMPLE 2,625,634

ELECTRIC HEATING Filed Aug. 30, 1960 1k \NI 27 f a II I lo I? 26 H 32 3 "iv-l8 I5 24 25 34 I4 I3 I 33 I9 23 I I 3 I l SIDNEY J. TEMPLE lNVENTOR ev "4 ATTORNEY Patented Jan. 13, 1953 ELECTRIC HEATING Si they J.

Temple, Swissvale, Pa., assignor to Edwin L. Wiegand Company, Pittsburgh, Pa, a corporation of Pennsylvania Application August 30, 1950, Serial No. 182,359

(01. Mil-67) 8 Claims.

My invention relates to electric heating, and the principal object of my invention is to provide an improvement in sheathed resistor electric heaters particularly in their terminal portions.

In the drawing accompanying this specification and forming a part of this application I have shown, for purposes of illustration, one mode of carrying my invention into practice, and in this drawing:

Figure 1 is a side View of an electric heater according to the selected mode;

Figure 2 is an enlarged central longitudinal section through one of the terminal portions of the heater of Figure 1;

Figure 3 is a section on the line of Figure 2; and

Figure 4 is a partial side elevation of the terminal extension shown in section in Figure 3.

For purposes of illustration I have shown a heater ll! of a type commonly known as a hairpin immersion heater, designed to be immersed in the liquid to be heated, and comprising a substantially circular tubular sheath H, a helical resistor l2 extending longitudinally of the sheath I 5, terminal pins It to which the ends of the resister 52 are connected, and suitable refractory material M, such as magnesium oxide, embed ding the resistor 52 and the inner portions of the terminal pins I 3.

According to the present embodiment of my invention, welded or otherwise secured fluid-tight to the ends of the sheath H, are tubular fittings $5 each provided with a flange iii, a smooth section I1, and a screw-threaded section it, and screw-threaded to the terminal pins 23 are terminal extensions 19 each extending substantially beyond the outer end of the respective fitting it, provided on the extending portion with a suitable screw thread 2% and provided within the fitting iii with a, fiat-sided section 2% and knurled sections 35 and 3%.

In the present embodiment, after the fittings l5 and terminal extension i9 been applied, at each terminal the outer portion of the terminal pin 13 and the inner portion of the terminal extension 19 to and including the flatsided section 2!, are embedded in further refractory material 22, preferably a suitable cement, such as a composition comprising granular zircon and a suitable clay, and the cement is set, as by firing at a suitable temperature.

Then there is introducedinto the remaining space within the fitting l5, a quantity or a suitable sealing material 23, such as that described in the copending application of Frederick E Hasley, led May 21, 1949, SerialNumber 94,649, and into this is introduced a ceramic bushing 24, after which a nut 25 is applied to the screw thread 28 of the respective terminal extension [9, and tightened to seat the bushing 24 and hold it in position, preferably with a suitable washer 26 interposed between the nut 25 and the bushing 24.

The described heater may conveniently be installed by projecting the two ends of the heater through apertures 27 in the wall 28 of the tank or duct or other container for the liquid to be heated, into position with the smooth sections [1 of the fittings it within the apertures 27 and the flanges is engaging the inner face of the wall '23, preferably with gaskets 29 interposed, then applying nuts S5 to the threaded sections (8 of the fittings i5 and drawin these nuts 30 against the outer of the wall 28, preferably with suitable washers 3i interposed, thus drawing the fitting flanges it into liquid-tight relation with the inner face of the wall 28.

Thereupon electrical connection may be made by applying electrical conductors 32 to theexposed portions of the threaded sections 20 of the terminal extensions it, and securing the conductors in position by means of nuts 33, preferably with washers 3 1 interposed, the cement 22 serving to retain the extensions l9 against rotation, particularly by reason of the irregular cross-section provided by the flat-sided sections 2! and the knurled sections 35.

However, as will be understood by those skilled in the art, various changes may be made, within the scope of my invention, and thus my invention is not to be regarded as limited to the present disclosure, but to be commensurate with the scope of the claims, and I claim:

l. A11 embedded-resistor electric heater com prising an op n-ended tubular sheath, an electrrcal resistor disposed withinsaicl sheath, 2; resister terminal member secured to one end of said resistor, an electrically insulating and heat conducting refractory material embedding said resiSt-DZ in said sheath, at least a portion of the length or said terminal member being free of embedding refractory material and accessible through the open end of said sheath, a tubular fitting secured to the open end of said sheath and continuing the tubular length of said sheath, tubular fitting being adapted to extend through a wall, a terminal extension secured to the terminal member and extending outwardly from the open end of said sheath aeaaesa and through said tubular fitting, at least a part of said terminal extension being irregular in cross-section, a refractory material embedding at least a portion of the irregular cross-sectional part of said terminal extension and thereby holding said terminal extension against rotation relative to said sheath, an external flange on said tubular fitting adapted to engage one face of a wall through which the tubular fitting extends, and an external threaded section on said tubular fitting in advance of said flange for receiving a nut for drawing said flange into sealing relation with said wall face.

2. An embedded-resistor electric heater comprising an open-ended tubular sheath, an electrical resistor disposed within said sheath, a resistor terminal member secured to one end of said resistor, an electrically insulating and heat conducting refractory material embedding said resistor in said sheath, at least a portion of the length of said terminal member being free of said embedding refractory material and accessible through the open end of said sheath, a tubular fitting secured to the open end of said sheath and continuing the tubular length of said sheath, said tubular fitting being adapted to extend through a wall, a terminal extension secured to the said terminal member and extending outwardly from the open end of said sheath and through said tubular fitting, at least a part of said terminal extension being irregular in cross-section, a cement-like refractory material embedding at least a portion of the irregular cross-sectional part of said terminal extension and thereby holding said terminal fitting against .rotation relative to said sheath, an external flange on said tubular fitting adapted to engage one face of a wall through which the tubular fitting extends, and an external threaded section on said tubular extension in advance of said flange for receiving a nut for drawing said flange into sealing relation with said wall face.

3. An embedded-resistor electric heater comprising an open-ended tubular sheath, an electrical resistor disposed within said sheath, a resistor terminal member secured to one end of said resistor, an electrically insulating and heat conducting refractory material embedding said resistor in said sheath, at least a portion of the length of said terminal member being free of saidembedding refractory material and accessible through the open end of said sheath, a tubular fitting secured to the open end of said sheath and continuing the tubular length of said sheath, said tubular fitting being adapted to extend through a wall, a terminal extension secured to the said terminal member and extending outwardly from the open end of said sheath and through said tubular fitting, at least a part of said terminal extension being irregular in cross-section, a set cementitious refractory material embedding at least a portion of the irregular cross-sectional part of said terminal extension and thereby holding said terminal extension against rotation relative to said sheath, an external flange on said tubular fitting adapted to engage one face of a wall through which the tubular fitting extends, and an external threaded section on said tubular fitting in advance of said flange for receiving a nut for drawing said flange intosealing relationwith said wall face.

" j 4. 5 Anembedded-resistor :electric heater comp'rising an open-ended tubular sheath, an electrical resistor disposed within said sheath, a resistor terminal member secured to one end of said resistor, an electrically insulating and heat conducting refractory material embedding said resistor in said sheath, at least a portion of the length of said terminal member being free of said embedding refractory material and accessible through the open end of said sheath, a tubular fitting secured to the open end of said sheath and continuing the tubular length of said sheath, said tubular fitting being adapted to extend through a wall, a terminal extension secured to the said terminal member and extending outwardly from the open end of said sheath and through said tubular fitting, at least a part of said terminal extension being irregular in cross-section, a refractory material embedding at least a portion of the irregular cross-sectional part of said terminal extension and thereby holding said terminal extension against rotation relative to said sheath, a seal for the open end of said tubular fitting, an external flange on said tubular extension adapted to engage one face of a Wall through which the tubular fitting extends, and an external threaded section on said tubular fitting in advance of said flange for receiving a nut for drawing said flange into sealing relation with said wall face.

:5. An embedded-resistor electric heater comprising an open-ended tubular sheath, an electrical resistor disposed within said sheath, a resistor terminal member secured to one end of said resistor, an electrically insulating and heat conducting refractory material embedding said resistor in said sheath, at least a portion of the length of said terminal member being free of said embedding refractory material and accessible through the open end of said sheath, a tubular fitting non-rotatably secured to the open end of said sheath and continuing the tubular length of said sheath, said tubular fitting being adapted to extend through a wall, a terminal extension secured to the said terminal member and extending outwardly from the open end of said sheath and through said tubular fitting, at least a, part of said terminal extension being irregular in cross-section, a refractory material embedding at least a portion of the irregular cross-sectional part of said terminal extension and thereby holding said terminal extension against rotation relative to said sheath, a seal for the open end of said tubular fitting, an external flange on said tubular fitting adapted to engage one face of a wall through which the tubular fitting extends, and an external threaded section on said tubular fitting in advance of said flange for receiving a nut for drawing said flange into sealing relation with said wall face.

6. An electric heater comprising a tubular sheath, an electrical resistor disposed within said sheath, electrical insulating material holding said resistor electrically insulated from said sheath and stopping short of the opening of said sheath to form a pocket, said resistor having a terminal extending through said pocket and outwardly of said sheath and said terminal having portions interlocking with said electrical insulating material to hold said terminal against movement, sealing material disposed within said pocket and about the adjacent portion of said resistor terminal, an apertured rigid plug fitting over said resistor terminal and within said pocket and against said sealing material, and fastening means interengaging with said resistor terminal outwardly of said sheath and bearing against, said plug to force the latter against said sealin'g'material and thereby press said sealing material into sealing engagement with adjacent surfaces of said sheath and said resistor terminal.

7. An electric heater comprising a tubular sheath, an electrical resistor disposed within said sheath, electrical insulating material holding said resistor electrically insulated from said sheath and stopping short of the opening of said sheath to form a pocket, said resistor having a threaded terminal extending through said pocket and outwardly of said sheath and said terminal having flatted portions interlocking with said electrical insulating material to hold said terminal against rotation, sealing material disposed within said pocket and about the adjacent portion of said resistor terminal, an apertured rigid plug fitting over said resistor terminal and within said pocket and against said sealing material, and a nut threaded on said terminal and bearing against said plug, said nut being capable of threading action to force said plug against said sealing material and thereby press said sealing material into sealing engagement with adjacent surfaces of said sheath and said resistor terminal.

8. An electric immersion heater adapted to be supported from the wall of a container, comprising a tubular sheath having exterior screw threads extending inwardly from an open end thereof and also having an abutment spaced inwardly from said end, an electrical resistor disposed within said sheath, electrical insulating material holding said resistor electrically insulated from said sheath and stopping short of said open end to form a pocket, said resistor having a threaded terminal extending through said pocket and outwardly of said open end and said terminal having flatted portions interlocking with said electrical insulating material to hold said terminal against rotation, sealing material disposed Within said pocket and about the adjacent portion of said resistor terminal, an apertured rigid plug fitting over said resistor terminal and Within said pocket and against said sealing material, a nut threaded on said terminal and bearing against said plug, said nut being capable of threading action to force said plug against said sealing material and thereby press said sealing material into sealing engagement with adjacent surfaces of said sheath and said resistor terminal, the threaded end of said sheath being adapted for disposal through an aperture in said container wall whereby said abutment engages one wall surface of said container wall and the threaded end of said sheath being adapted to receive a nut disposed on the opposite wall surface of said container for drawing said abutment against said one wall surface.

SIDNEY J. TEMPLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,494,940 Abbott May 20, 1924 2,217,595 Morgan et al. Oct. 8, 1940 2,310,325 Smith Feb. 9, 1943 FOREIGN PATENTS Number Country Date 218,393 Great Britain July 7, 1924 266 151 Great Britain Feb. 24 1927 

